Relationships Among Mass Capacity, Speed, And Acceleration/Deceleration Speed; Setting Load Capacity And Size (Hand Conditions); Vibrations At The Tip Of The Arm During Low-Speed Operation Of The Robot; Collision Detection - Mitsubishi Electric RV-8CRL Standard Specifications Manual

2.2.3 Relationships Among Mass Capacity, Speed, and Acceleration/Deceleration Speed

This robot automatically sets the optimum acceleration and deceleration speeds and maximum speed,
according to the load capacity and size that have been set, and operates using these automatically set
speeds.
To achieve that, it is necessary to correctly set the actual load data (mass and size of hand and work) to be
used. However, vibration, overheating and errors such as excessive margin of error and overload may
occur, depending on the robot operation pattern or ambient temperature. In such a case, change the setting
value to the +20% range.
If a setting is performed in such a way that it falls below the mounted load, the life span of the mechanism
elements used in the robot may be shortened.

(1) Setting Load Capacity and Size (Hand Conditions)

Set up the capacity and size of the hand with the "HNDDAT*" parameter (optimum acceleration/deceleration
setting parameter), and set up the capacity and size of the work with the "WRKDAT*" parameter. Numbers 0
to 8 can be used for the asterisk (*) part. Designate the "HNDDAT*" and "WRKDAT*" parameters to be used
using the "LoadSet" command in a program.
For more details, refer to the separate "Instruction Manual/Detailed Explanation of Functions and Opera-
tions."
It is the same meaning as "LoadSet 0.0" if not using the "LoadSet".
<Factory settings>
Hand mass
HNDDAT* = 8.0
WRKDAT* = 0.0

2.2.4 Vibrations at the Tip of the Arm during Low-Speed Operation of the Robot

Vibrations at the tip of the arm may increase substantially during the low-speed operation of the robot,
depending on the combination of robot operation, hand mass and hand inertia. This problem occurs when
the vibration count specific to the robot arm and the vibration count of the arm driving force are coming close
to each other. These vibrations at the tip of the arm can be reduced by taking the following measures:
1) Lower the robot's operating speed by approximately 5% from high speed using the Ovrd command.
2) Change and move the teaching points of the robot.
3) Change the hand mass and hand inertia.

2.2.5 Collision detection

This series have the "collision detection function" which detects the abnormalities by the collision of the
robot arm, however initial setting is in invalid condition.
The enable/disable of this function can be changed by parameter: COL and command: ColChk, this function
is effective for protect of the robot and of the peripheral equipment.
The abnormalities are detected by the robot's kinetics model, presuming torque necessary for movement at
any time. Therefore, the setting parameter (HNDDAT*, WRKDAT*) of the hand and the work piece condi-
tions should be right. And, it may be detected as the collision in movement as speed and motor torque are
changed rapidly. (for example, the movement near the place of the origin by linear interpolation, the reversal
movement, the cold condition, the operation after long term stoppage)
In such a case, by adjusting the value of the setting parameter (COLLVL, COLLVLJG) of the collision detec-
tion level according to actual use environment, the sensitivity of collision detection can be optimized and the
damage risk can be reduced further. And, in the operation after the low temperature or long term stoppage,
please operate by accustoming at low speed (warm-up), or use the warm-up operation mode.
Refer to the separate instruction manual "Detailed explanations of functions and operations" for details of
related parameter.
Table 2-3: Factory-shipments condition
RV-8CRL
Size X
[kg] [mm]
100.0 100.0
0.0
Size Y Size Z Center-of-grav-
ity position X
[mm] [mm]
100.0
0.0 0.0
JOG operation
Invalid
Center-of-grav-
ity position Y
[mm] [mm]
0.0 0.0
0.0 0.0
Automatic
Invalid
2 Robot arm
Center-of-grav-
ity position Z
[mm]
155.0
0.0
2-13